View full sizeNASAJust in time for the telescope’s 20th anniversary, NASA released this new photo of a small portion of one of the largest known star-birth regions in the galaxy, the Carina Nebula. The nebula is a cold cloud of predominantly hydrogen gas. It is laced with dust, which makes the cloud opaque. The cloud is being eroded by a gusher of ultraviolet light from young stars in the region. They sculpt a variety of fantasy shapes, many forming tadpole-like structures.

It’s been two decades since NASA sent the Hubble Space Telescope on its ambitious journey, 350 miles above us, doing laps around the Earth.

Two decades of awesome photography, offering humans a glimpse of distant galaxies and a look back in time, billions and billions of years ago.

The age of the universe. Scientists have long pondered how old it is, offering different estimates. Hubble measured the brightness of pulsating stars called Cepheid variables, helping astronomers figure out how far they were from Earth. Their computations set the universe’s age at 13.7 billion years.

The prevalence of massive black holes. Most galaxies have them. The Hubble computed the mass of black holes by measuring how fast material was moving around them. The telescope also helped determine that a black hole’s mass is proportional to the mass of its galaxy, so that, for example, a galaxy twice as massive as another would have a black hole that is also twice as massive. The gravity of black holes is so strong it pulls in everything else.

How planets form. A cloud of gas and dust collapses under its gravity. The central region forms a star, becoming denser, which raises pressure and temperature and fuses atoms together. The star’s gravity pulls the remaining cloud matter around it in an orbit, forming a disk that eventually forms planets. The Hubble has allowed scientists to compare disks of dust and gas around younger stars with those around older stars.

NASAHubble drifts over Earth after its release on May 19, 2009, by the crew of the Space Shuttle Atlantis.

The existence of dark energy. A mysterious form of energy pushes galaxies away from each other at increasing speeds — fighting the force of gravity. Astronomers made the discovery thanks to Hubble’s images of bursts of light from stars exploding far away. Hubble detected dark energy back to 9 billion years ago. The discovery brings many more questions — astronomers know very little about dark energy.

How galaxies grow. Hubble’s photos of deep space show that galaxies join together to become bigger galaxies. Most helpful were “Deep Field” observations that found galaxies very far away are smaller and more irregularly shaped than those of today — because they haven’t combined with other galaxies yet.

Hubble's discoveries have revolutionized nearly all areas of current astronomical research from planetary science to cosmology. Actor and writer Brent Spiner narrates a visual journey back in time and into the farthest reaches of the cosmos.

Hubble 20th: Carina Nebula video

This zoom video shows the location of Hubble's 20th anniversary image of the Carina Nebula in the sky. (no audio)

Celebrating 20 Years of Hubble video

NASA's Hubble Space Telescope began a remarkable journey of discovery on April 24, 1990. After 20 years in space, the observatory has shown humanity more of the universe than ever before. With the help of the space shuttle, astronauts clarified Hubble's vision, then sharpened with ever-improving instruments.

More images:

NASAThis is a series of close-up views of the complex gas structures in a small portion of the Carina Nebula. The nebula is a cold cloud of predominantly hydrogen gas. It is laced with dust, which makes the cloud opaque. The cloud is being eroded by a gusher of ultraviolet light from young stars in the region. They sculpt a variety of fantasy shapes, many forming tadpole-like structures. In some frames, smaller pieces of nebulosity can be seen freely drifting, such as the 2.3-trillion-mile-long structure at upper right. The most striking feature is a 3.5-trillion-mile-long horizontal jet in the upper left frame. It is being blasted into space by a young star hidden in the tip of the pillar-like structure. A bowshock has formed near the tip of the jet.